Answer:
1.5 g/cm
3
Let d be the density of fluid.
So , Initial reading of balance, F
1
=30dg N
After the level reaches 50cm
3
Final reading of balance , F
2
=50dg N
Given that difference between final and initial reading is 30g
i.e, F
2
−F
1
=30 g
⟹50dg−30dg=30g
⟹20dg=30g
⟹d=
20g
30g
⟹d=1.5g/cm
3
So, density of fluid is 1.5g/cm
3